JP4368277B2 - Receiver - Google Patents

Description

  The present invention relates to a receiving apparatus capable of connecting a plurality of receivers, and more particularly to an LNB (Low Noise Block down converter) constituting a satellite broadcast receiving system.

  FIG. 3 is a block diagram showing a conventional example of LNB. The LNB 100 shown in this figure extracts a plurality of channel signals from a satellite signal received via a reflector (not shown), amplifies them with low noise, and selectively receives a channel signal required by the receivers 200a and 200b. , The power supply circuit 102 for generating the power supply voltage of the LNB 100, and the ports 103a and 103b to which the receivers 200a and 200b are respectively connected. The power supply circuit 102 includes diodes Da and Db whose anodes are connected to the ports 103a and 103b and whose cathodes are connected to each other, and regulators REG1 and REG2 whose input ends are connected to both cathodes of the diodes Da and Db, It has.

  In the LNB 100 having the above configuration, the power supply circuit 102 is supplied with the DC voltages Va and Vb from the receivers 200a and 200b via the ports 103a and 103b, and the regulators REG1 and REG2 are supplied from the DC voltages Va and Vb. DC voltages VA and VB (for example, 5 [V] and 6 [V]) are generated and supplied to each part of the LNB 100.

  The DC voltages Va and Vb are used as input voltages for the regulators REG1 and REG2, and are also used as output selection signals for the receiving circuit 101. Each of the DC voltages Va and Vb has a plurality of voltage levels according to the frequency band of the desired channel signal. (For example, binary of 13 [V] and 18 [V]). At this time, if the DC voltage Va is higher than the DC voltage Vb, only the diode Da is turned on, and the DC voltage Va is used as the input voltage of the regulators REG1 and REG2. Conversely, when the DC voltage Vb is higher than the DC voltage Va, only the diode Db is turned on, and the DC voltage Vb is used as the input voltage of the regulators REG1 and REG2.

  In the case of the LNB 100 having the above configuration, even when a difference occurs in the DC voltages Va and Vb respectively applied to the ports 103a and 103b when the reception channel is switched, the rectifying action of the diodes Da and Db causes a high potential. Since a backflow current from the port to the low potential port is prevented, receiver breakdown due to the backflow current can be avoided.

  However, in the configuration in which the currents Ia and Ib respectively supplied from a plurality of connected receivers 200a and 200b are simply added together and consumed as in the LNB 100 having the above-described configuration, a difference occurs in the DC voltages Va and Vb. Therefore, the entire current consumption of the LNB 100 is drawn only from the receiver that supplies a higher voltage, and no current is drawn from the other receiver. Therefore, in the LNB 100 configured as described above, the currents Ia and Ib fluctuate greatly each time the magnitude relationship between the DC voltages Va and Vb is reversed when the reception channel is switched, and the noise caused by the current fluctuation causes the LNB 100 to change. There was a problem that malfunction and disturbance of received video were invited.

Therefore, in order to solve the above-mentioned problem, when a plurality of receivers are conventionally connected, current is preferentially drawn from the receiver connected to a predetermined port regardless of the magnitude of the DC voltage supplied from each receiver. The present applicant discloses and proposes such a receiving device and a receiving device in which a constant current is drawn from each of a plurality of connected receivers by equally distributing all current consumption of the device to each port. (See Patent Documents 1 and 2).
JP 2002-218329 A JP 2001-127661 A

  Certainly, with the receiving devices of Patent Documents 1 and 2 described above, even when a change occurs in the magnitude relationship of DC voltages applied from a plurality of connected receivers when switching reception channels, they are drawn from each receiver. Since the current does not fluctuate, noise due to the current fluctuation does not occur, and a malfunction of the receiving device and a disturbance of the received video are not caused.

  However, since the receiver of Patent Document 1 cannot utilize the current supply capability of the receiver connected to other than the predetermined port at all, if a receiver with a low current supply capability is connected to the predetermined port, the other Even if a receiver having a high current supply capability is connected to the port, there is a risk that normal operation may not be possible due to insufficient current supply.

  Further, in the receiving device of Patent Document 2 (see FIG. 4), the total current consumption of the device cannot necessarily be equally distributed to the ports 103a and 103b due to component variations of the equal distribution circuit DIV. There was a problem that a difference in the current value drawn from 200b occurred. Further, the equal distribution performance of the equal distribution circuit DIV is determined according to the input voltage variation in addition to the above-described component variation. For example, when a regulator for each port is provided in the preceding stage of the equal distribution circuit DIV Even so, there is a problem that the difference in the current value drawn from each of the receivers 200a and 200b is caused by the slight variation in output voltage. Furthermore, in the receiving device using the equal distribution circuit DIV, the circuit configuration becomes complicated, and there is a problem that the cost of the device is increased and the mounting area of the circuit is increased.

  As another configuration that does not cause fluctuations in the current drawn from each of the connected receivers, the current consumption control may be performed in detail using a transistor switch or a microcomputer. However, in such a configuration, since it takes time for the on / off switching control of the transistor switch and the signal processing of the microcomputer, it cannot follow the instantaneous voltage fluctuation (for example, the on / off of the receiver), and the receiving apparatus has a problem. (Instantaneous voltage drop, etc.) may occur.

  In view of the above-described problems, the present invention provides a receiver that has a simple circuit configuration but does not cause fluctuations in current drawn from each of them even if supply voltages of a plurality of connected receivers fluctuate instantaneously. The purpose is to do.

In order to achieve the above object, a receiving apparatus according to the present invention includes a plurality of external terminals to which a receiver is attached and detached, a plurality of internal circuits each having a different power supply path, and a power supply from the receiver. A power supply circuit that generates a drive voltage for an internal circuit, wherein the power supply circuit includes a pre-stage regulator provided for each power supply path from the external terminal, and an output of each pre-stage regulator If the potential difference between the terminals is larger than a predetermined threshold value, a bypass unit that short-circuits between the output terminals, and a drive voltage for the internal circuit is provided from the output voltage of the front-stage regulator provided on the downstream side of the bypass unit. a main regulator for generating and possess, the bypass portion, a pair of diodes connected in parallel in opposite directions over between output ends cross each preceding stage regulator Properly is a structure consisting of a diode string. By adopting such a configuration, even though the supply voltage of a plurality of connected receivers fluctuates instantaneously, there is no fluctuation in the current drawn from each of them even though the circuit configuration is simple. The resulting noise does not occur, and it is possible to avoid malfunction of the receiving apparatus and disturbance of the received video.

In addition , the above-described bypass portion can be realized extremely simply and can sufficiently follow instantaneous voltage fluctuations. In addition, if the bypass unit is composed of a pair of diodes connected in reverse parallel, the threshold for short-circuiting the output terminals of the respective front regulators can be increased compared to the case where a single diode is paired. Even if the output voltage of the pre-stage regulator varies slightly, it is possible to avoid malfunction of the bypass unit.

  As described above, the receiving apparatus according to the present invention has a simple circuit configuration, but even if the supply voltage of a plurality of connected receivers fluctuates instantaneously, the current drawn from each does not fluctuate. Therefore, it is possible to prevent malfunction of the apparatus and disturbance of the received video.

  FIG. 1 is a block diagram showing a first embodiment of an LNB according to the present invention. As shown in this figure, the LNB 10 according to the present invention extracts a plurality of channel signals from a satellite signal received via a reflector (not shown), amplifies them with low noise, and selects the channel signals required by the receivers 20a and 20b. The receiving circuit 11 for sending out, the power supply circuit 12 for generating the power supply voltage of the LNB 10, and the ports 13a and 13b to which the receivers 20a and 20b are connected, respectively.

  In the LNB 10 having the above-described configuration, the power supply circuit 12 is supplied with the DC voltages Va and Vb from the receivers 20a and 20b via the ports 13a and 13b. The power supply circuit 12 is supplied with the predetermined voltages from the DC voltages Va and Vb. DC voltages VA and VB (5 [V] and 6 [V]) are generated and supplied to internal circuits A and B having different power supply paths. The internal circuits A and B are obtained by dividing the internal circuit of the LNB 10 into a plurality based on the power consumption and the correlation with the receiver. The LNA [Low Noise Amplifier], the local oscillator, Includes a mixer, a selector, and the like.

  Further, the DC voltages Va and Vb given from the receivers 20a and 20b are used as the input voltage of the power supply circuit 12, and are also used as the output selection signal of the receiving circuit 11, depending on the frequency band of the desired channel signal. , Each is changed to a plurality of voltage levels (for example, binary values of 13 [V] and 18 [V]).

  Here, the power supply circuit 12 according to the present embodiment includes a pre-stage regulator PRa, PRb provided for each power supply path from the ports 13a, 13b, and a backflow prevention in which anodes are connected to the output terminals of the pre-stage regulators PRa, PRb. If the potential difference between the diodes Da and Db and the cathodes of the backflow prevention diodes Da and Db (that is, between the output terminals of the front-stage regulators PRa and PRb) is larger than a predetermined threshold, the output terminals are short-circuited. A bypass unit BP and main regulators REG1 and REG2 which are provided on the rear side of the bypass unit BP and generate the drive voltages VA and VB of the internal circuits A and B from the output voltages Va ′ and Vb ′ of the front-stage regulators PRa and PRb; , Comprising.

  The pre-stage regulators PRa and PRb are designed so that their output voltages Va ′ and Vb ′ are the same (for example, 9 [V]).

  The bypass section BP is configured by a pair of bypass diodes 1 and D2 connected in parallel in opposite directions across the cathodes of the backflow prevention diodes Da and Db. More specifically, the anode of the bypass diode D1 and the cathode of the bypass diode D2 are connected to the cathode of the backflow prevention diode Da, and the cathode of the bypass diode D1 and the anode of the bypass diode D2 are connected to the backflow prevention diode Db. Connected to the cathode.

  In the LNB 10 configured as described above, when the receivers 20a and 20b are connected to both the ports 13a and 13b, the same output voltages Va ′ and Vb ′ are generated in the pre-regulators PRa and PRb. . Therefore, unless the output voltages Va ′ and Vb ′ are excessively varied, the voltage across the bypass diodes D1 and D2 is less than the forward voltage drop (about 0.7 [V] for silicon diodes). Become. As a result, the bypass unit BP is in a non-shorted state (a state in which no current flows through the bypass diodes D1 and D2), so that the power supply path from the port 13a to the main regulator REG1 and the power supply from the port 13b to the main regulator REG2 The paths are established, and the consumption currents IA and IB of the internal circuits A and B are drawn from the receivers 20a and 20b connected to the ports 13a and 13b, respectively.

  On the other hand, when the receiver 20a is connected only to the port 13a, the output voltage Va ′ is generated only by the pre-stage regulator PRa, and the voltage across the bypass diode D1 is higher than the forward voltage drop. growing. As a result, the bypass unit BP is in a short-circuit state (a state in which current flows through the bypass diode D1), so that the power supply path from the port 13a to the main regulator REG1 and the port 13a to the main regulator REG2 via the bypass unit BP as well. Are respectively established, and current consumptions IA and IB of the internal circuits A and B are all drawn from the receiver 20a connected to the port 13a.

  Similarly, when the receiver 20b is connected only to the port 13b, the output voltage Vb ′ is generated only by the pre-stage regulator PRb, and the voltage across the bypass diode D2 is less than the forward drop voltage. Also grows. As a result, the bypass unit BP is in a short-circuited state (a state in which current flows through the bypass diode D2), so that the power supply path from the port 13b to the main regulator REG2 and also from the port 13b to the main regulator REG1 via the bypass unit BP. Are respectively established, and current consumptions IA and IB of the internal circuits A and B are all drawn from the receiver 20b connected to the port 13b.

  As described above, the pre-stage regulators PRa and PRb are provided for each power supply path from the ports 13a and 13b, and the potential difference between the output terminals of the pre-stage regulators PRa and PRb is a predetermined threshold value (in the present embodiment, the bypass diode D1). , D2 forward voltage drop), a bypass unit BP that short-circuits the output terminals is provided, and main regulators REG1 and REG2 provided on the subsequent stage side are used to output the output voltages of the preceding regulators PRa and PRb. By adopting a configuration in which the drive voltages VA and VB of the internal circuits A and B are generated from Va ′ and Vb ′, the supply voltages Va and Vb of the receivers 20a and 20b fluctuate instantaneously while having a simple circuit configuration. Even in this case, the consumption currents Ia and Ib drawn from each of the currents do not fluctuate. It without the noise caused by the movement occurs, it is possible to avoid disturbance of the malfunction and received video of LNB 10.

  In addition, since the LNB 10 of the present embodiment is configured to distribute the consumption currents Ia and Ib of the internal circuits A and B only according to the short circuit / non-short circuit of the bypass unit BP, the receiver 20a is provided to both the ports 13a and 13b. , 20b are connected, even if the output voltages Va ′, Vb ′ of the pre-stage regulators PRa, PRb vary slightly, the current values drawn from the receivers 20a, 20b do not differ, and the receivers 20a, 20b, It becomes possible to always consume a constant current from 20b. That is, with the LNB 10 of the present embodiment, it is possible to calculate the current consumption from the receivers 20a and 20b in advance without considering the input voltage variation and component variation.

  Further, as described above, the bypass unit BP of the present embodiment includes a pair of bypass diodes D1 and D2 that are connected in parallel in opposite directions across the output ends of the front-stage regulators PR1 and PR2. ing. By adopting such a configuration, the bypass unit BP can be realized extremely easily, and can sufficiently follow instantaneous voltage fluctuations caused by turning on / off the receivers 20a and 20b and switching the reception channel. It becomes.

  In the first embodiment, as an example, the circuit configuration of the bypass unit BP includes one bypass diode D1 and D2 for each bypass path, and they are connected in parallel in opposite directions. Although described above, the configuration of the present invention is not limited to this, and a pair of diode arrays in which a plurality of bypass diodes are connected in series is prepared instead of a single bypass diode, and they are connected to each other. A configuration in which they are connected in parallel is also acceptable.

  As a specific configuration example, as shown in the second embodiment of FIG. 2, a first diode array formed by connecting bypass diodes D11 and D12 in series and a bypass diode D21 and 22 connected in series are provided. Two diode arrays may be prepared, and the output terminals of the front-stage regulators PR1 and PR2 may be connected in parallel in opposite directions across the output ends.

  By adopting such a configuration, the threshold value for short-circuiting between the output terminals of the front-stage regulators PRa and PRb can be increased as compared with the first embodiment described above. Therefore, the output voltage Va of the front-stage regulators PRa and PRb can be increased. Even if “, Vb” slightly varies, it is possible to avoid the malfunction of the bypass unit BP.

  That is, in the first embodiment in which one bypass diode is provided for each bypass path, when the voltage between both ends exceeds the forward drop voltage (about 0.7 [V]) of one bypass diode. Although the bypass path is short-circuited, in the second embodiment in which two bypass diodes are provided for each bypass path, the potential across the diode array has a forward drop voltage (about 1.. As long as 4 [V]) is not exceeded, the bypass path is not short-circuited. Therefore, for example, when a difference of 1 [V] occurs in the output voltages Va ′ and Vb ′ of the upstream regulators RPa and RPb, in the first embodiment, the bypass unit BP is short-circuited due to malfunction, but the second implementation If it is a form, such a malfunction does not arise and it becomes possible to perform more stable current control.

  In the second embodiment, the description has been given by taking as an example a configuration in which two bypass diodes are provided for each bypass path. However, the configuration of the present invention is not limited to this, and the previous stage Even if the voltage drop at the bypass unit BP is taken into account from the output voltages Va ′ and Vb ′ of the regulators PRa and PRb, the bypass diode is appropriately used within the range in which the main regulators REG1 and REG2 can generate the output voltages VA and VB. Can be 3 stones or more.

  In the first and second embodiments described above, for ease of explanation, the number of receivers connected to the LNB 10 is two, and the internal circuit of the LNB 10 is divided into two as an example. However, the configuration of the present invention is not limited to this, and it is possible to arbitrarily set the number of connected receivers and the number of divided internal circuits.

  The configuration of the present invention can be variously modified within the scope of the present invention in addition to the above embodiment.

  In the above embodiment, the case where the present invention is applied to the LNB configuring the satellite broadcast receiving system has been described as an example. However, the application target of the present invention is not limited to this, and the receiver is not limited to this. The present invention can be widely applied to a plurality of receiving apparatuses connected in general.

  The present invention is suitable for an LNB or the like constituting a satellite broadcast receiving system, and is a very useful technique as a means for preventing malfunction of the apparatus and disturbance of received video.

These are block diagrams which show 1st Embodiment of LNB which concerns on this invention. These are block diagrams which show 2nd Embodiment of LNB which concerns on this invention. These are block diagrams which show a prior art example of LNB. These are block diagrams which show another prior art example of LNB.

Explanation of symbols

10 LNB
11 Receiver circuit 12 Power supply circuit PRa, PRb Pre-stage regulator Da, Db Backflow prevention diode BP Bypass unit D1, D2 Bypass diode (D11, D12), (D21, D22) Bypass diode string REG1, REG2 Main regulator A, B Internal circuit 13a , 13b Port 20a, 20b Receiver

Claims (1)

A plurality of external terminals to which each receiver is attached and detached, a plurality of internal circuits each having a different power supply path, and a power supply circuit that receives power supply from the receiver and generates a drive voltage for the internal circuit. A receiving device comprising:
The power supply circuit includes a bypass unit that short-circuits between the output terminals of the front-stage regulator provided for each power supply path from the external terminal and the output terminals of each front-stage regulator if the potential difference between the output terminals is larger than a predetermined threshold value. If, have a, a main regulator for generating a driving voltage of the internal circuit from the output voltage of the previous stage regulator disposed downstream side of the bypass section,
The receiving apparatus according to claim 1, wherein the bypass unit includes a pair of diodes or diode arrays connected in parallel in opposite directions across the output terminals of the respective front-stage regulators .

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